Carbide Compounds
Binary compounds formed by carbon atoms and most electropositive elements (except hydrogen) are called carbides. Based on the type of bond formed between the carbon and the electropositive element, there are three types of carbide compounds.
1. Ionic carbide compounds
The ionic carbide compound is formed when the carbon atom is bonded to the most electropositive elements, alkali, alkaline, and aluminum. Most ionic carbide compounds contain dicarbide (2-) ions on their carbon atoms.
The ionic carbide compounds are solid at room temperature and have a hard structure. The ionic carbide compound is the only chemically reactive carbide compound.
Example:
Sodium carbide (Na2C2) reacts with water to produce ethanol gas (acetylene).
Some ionic carbide compounds also contain carbon ions with -4 charge, such as beryllium carbide (Be2C) red and aluminum carbide (Al4C3) are yellow. This is because the Be2 + and Al3 + ions are cations with high charge densities (although their ion size is smaller) that can stabilize the high-charged anions such as carbide ions (C-4, a large sized of anion).
Beryllium and aluminum carbide reacts with water to produce methane gas, wherein methane compounds there are carbon ions with a -4 charge.
2. Covalent Carbide Compounds
The number of these compounds is very small since most nonmetallic elements are more electronegative than carbon. Silicon carbide, SiC and boron carbide, B4C are two examples of covalent carbide compounds.
Both compounds are very hard and have a high melting point. Silicon carbide is used as a polishing agent on the metal surface and is the only non-oxide ceramic product produced on a large scale annually.
The pure silicon carbide is green and is made in a special furnace called the Acheson furnace. The raw materials for making SiC are silicon dioxide and carbon. This furnace should be heated first so that the temperature reaches 2300 degC (takes about 18 hours) so the reaction can take place.
The final product (SiC), can only be produced after the reaction takes place about 18 hours later in the furnace. Thus, it can be said that the SiC-making reaction requires enormous electrical energy, which is about 6-12 kWh for every 1 kg of silicon carbide.
Silicon carbide is widely used for:
Other uses of silicon carbide are still under investigation. Perhaps, in the years ahead, silicon carbide can be widely used in many areas of life.
3. Metal Carbide Compounds
Metal carbide compounds are formed when carbon atoms are trapped within the crystal structure of a metal (usually transition metals). More precisely, this carbon atom is trapped in a hole contained in the octahedral structure of the metal crystals.
Since the metal carbide compound contains a metal, it looks like a metal element and can conduct electricity. Similar to other carbide compounds, carbide compounds are important because they have a very high melting point, resistant to chemical reactions, and extremely hard.
The most important compound of this group is tungsten carbide (WC) which is widely used as raw material for making cutting tools.
1. Ionic carbide compounds
The ionic carbide compound is formed when the carbon atom is bonded to the most electropositive elements, alkali, alkaline, and aluminum. Most ionic carbide compounds contain dicarbide (2-) ions on their carbon atoms.
The ionic carbide compounds are solid at room temperature and have a hard structure. The ionic carbide compound is the only chemically reactive carbide compound.
Example:
Sodium carbide (Na2C2) reacts with water to produce ethanol gas (acetylene).
Some ionic carbide compounds also contain carbon ions with -4 charge, such as beryllium carbide (Be2C) red and aluminum carbide (Al4C3) are yellow. This is because the Be2 + and Al3 + ions are cations with high charge densities (although their ion size is smaller) that can stabilize the high-charged anions such as carbide ions (C-4, a large sized of anion).
Beryllium and aluminum carbide reacts with water to produce methane gas, wherein methane compounds there are carbon ions with a -4 charge.
2. Covalent Carbide Compounds
The number of these compounds is very small since most nonmetallic elements are more electronegative than carbon. Silicon carbide, SiC and boron carbide, B4C are two examples of covalent carbide compounds.
Both compounds are very hard and have a high melting point. Silicon carbide is used as a polishing agent on the metal surface and is the only non-oxide ceramic product produced on a large scale annually.
The pure silicon carbide is green and is made in a special furnace called the Acheson furnace. The raw materials for making SiC are silicon dioxide and carbon. This furnace should be heated first so that the temperature reaches 2300 degC (takes about 18 hours) so the reaction can take place.
The final product (SiC), can only be produced after the reaction takes place about 18 hours later in the furnace. Thus, it can be said that the SiC-making reaction requires enormous electrical energy, which is about 6-12 kWh for every 1 kg of silicon carbide.
Silicon carbide is widely used for:
- Used to make turbine blades that operate at high temperatures. Typically turbine blades are made of metal. Metals can lose strength when operating at high temperatures. Because silicon carbide has a much higher melting point than metal, making it suitable for blade turbines.
- Used to synthesize organosilicon compound fluids.
Other uses of silicon carbide are still under investigation. Perhaps, in the years ahead, silicon carbide can be widely used in many areas of life.
3. Metal Carbide Compounds
Metal carbide compounds are formed when carbon atoms are trapped within the crystal structure of a metal (usually transition metals). More precisely, this carbon atom is trapped in a hole contained in the octahedral structure of the metal crystals.
Since the metal carbide compound contains a metal, it looks like a metal element and can conduct electricity. Similar to other carbide compounds, carbide compounds are important because they have a very high melting point, resistant to chemical reactions, and extremely hard.
The most important compound of this group is tungsten carbide (WC) which is widely used as raw material for making cutting tools.
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